This invention relates generally to a data storage tape cartridge and more particularly to a data storage tape cartridge having a compliant guide.
Cartridges have been used for decades in the computer, audio and video fields. The data storage tape cartridge continues to be an extremely popular form for recording large volumes of information for subsequent retrieval and use.
A data storage tape cartridge generally consists of an outer shell or housing maintaining at least one tape reel assembly and a length of magnetic storage tape. The storage tape is wrapped about a hub portion of a tape reel and is driven through a defined tape path by a driving system. The housing normally includes a separate cover and base, the combination of which forms an opening (or window) at a forward portion thereof for allowing access to the storage tape by a read/write head upon insertion of the data storage tape cartridge into a tape drive. This interaction between storage tape and head may take place within the housing, or the storage tape may be directed away from the housing to an adjacent area at which the read/write head is located. Where the tape cartridge/drive system is designed to direct the storage tape away from the housing, a single tape reel assembly is normally employed. Conversely, where the tape cartridge/drive system is designed to provide head/storage tape interaction within or very near the housing, a two or dual-tape reel assembly configuration is typically utilized.
The wear on the edges of the storage tape is one of the primary sources of debris in most tape magnetic media storage systems. One reason that the tape edges wear is that the load force must be high enough to constrain the tape motion at the head to specifications established by the tape drive. Reducing the guiding force allows more tape motion at the head and leads to tracking problems. Increasing the force causes excessive edge wear. One of the problems with manufacturing the guide is that the tape makes limited contact on the member that applies the force, such as a foil. This causes high pressure and accelerates the tape wear. Ideally, the force on the tape edges is spread out over a maximum area on the foil, thereby minimizing pressure on the tape. However, due to the fact that the foils are typically stamped metal parts and the tolerances that are built up in the assembly of the tape guide, it is difficult to construct an economical tape guide wherein the foil contacts the tape along its entire length.
Some foils have spring mountings so that they can move slightly when there is a force applied by the tape. However, it has been found that the foil force does not change significantly when such displacement occurs. Therefore, there is still continued wear on the tape edges. The load applying member or foil is typically constructed from stainless steel in the prior art. However, because of the economical constraints in making the foil used in the tape guides of the prior ark the foil does not contact the edge of the tape along its entire length. Instead, the tape contacts the foil at points or discrete segments. As such, the force is applied over a smaller area than possible, thereby resulting in higher pressure and therefore more tape edge wear.
Data storage tape cartridges are important tools to maintain vast amounts of information. To remain competitive, data storage tape cartridge manufacturers may continually improve cartridge performance and reliability while reducing manufacturing costs. Therefore, the need exists to manufacture a data storage tape cartridge which is effective and provides for an effective tape guide.
In one embodiment, the invention is a data storage tape cartridge having a baseplate having a head opening formed therein. A tape reel assembly is rotatably mounted on the baseplate and a storage tape is wound around the tape reel assembly. A tape guide is operably connected to the baseplate proximate the head opening. The tape guide has a bearing surface. The bearing surface has first and second edges. The tape guide also includes a load applying member, the load applying member extending from proximate one of said edges, wherein the tape is positioned over the bearing surface and an edge of the tape is in contact with the load applying member resulting in a load force applied to the load applying member. The load applying member is constructed from a material of a hardness that causes a wear pattern to be formed on the load applying member by the tape, thereby spreading the force over a larger area. The wear pattern has a depth of 0.1 microns or greater and a length that is 50 percent or greater of the load applying member over which the tape passes.
In a second embodiment, the invention is a data storage tape cartridge having a baseplate having a head opening formed therein. A tape reel assembly is rotatably mounted on the baseplate and a storage tape is wound around the tape reel assembly. The tape guide is operably connected to the baseplate proximate the head opening. A tape guide has a bearing surface. The bearing surface has first and second edges. The tape guide also includes a load applying member, the load applying member extending from proximate one of said edges, wherein the tape is positioned over the bearing surface and an edge of the tape is in contact with the load applying member resulting in a load force applied to the load applying member. The load applying member has an outer layer having a first hardness and an inner layer having a second hardness, the second hardness being greater than the first hardness.
In a third embodiment, the invention is a data storage tape cartridge having a baseplate having a head opening formed therein. A tape reel assembly is rotatably mounted on the baseplate and a storage tape is wound around the tape reel assembly. The tape guide is operably connected to the baseplate proximate the head opening. A tape guide has a bearing surface. The bearing surface has first and second edges. The tape guide also includes a load applying member, the load applying member extending from proximate one of said edges, wherein the tape is positioned over the bearing surface and an edge of the tape is in contact with the load applying member resulting in a load force applied to the load applying member. The load applying member is constructed from a multi-phase material having a first phase and a second phase, the second phase harder than the first phase.